Researchers at the University of Newcastle have achieved a breakthrough in recovering silver from decommissioned photovoltaic modules via froth flotation, a conventional mineral processing technique widely used in mining, marking the world’s first continuous pilot-scale trial of the acid-free method.

The team recovered nearly 100% of silver from roughly half a tonne of end-of-life PV hardware. The pilot processed 22 kg of solar cell material sourced from around 460 kg of retired panels, equivalent to approximately 23 residential solar modules. The recovered silver was concentrated into a stream around 80 times richer in silver than the original cell feedstock.

Prior bench-scale batch tests had proven froth flotation could extract silver without costly, hazardous acid. The new continuous pilot addresses the key commercial hurdle: scalable, economical recovery to make PV recycling viable.

Associate Professor Mahshi Firouzi, Deputy Director of the University of Newcastle’s Centre for Critical Minerals and Urban Mining, said the focus has shifted from technical feasibility to commercial scale.

“Our earlier small-scale batch research proved flotation could recover silver from solar panels. This latest work demonstrates that the process can operate continuously at a much larger scale with nearly 100% silver recovery, bringing us closer to commercial implementation.”

Preliminary modelling indicates the flotation route could be 3–5 times more cost-effective than standard acid leaching, while removing the complexity and risks of hazardous waste handling.

In Australia, recycling one PV module currently costs about AU$10–15, whereas landfill disposal is only a few dollars per unit — an uneconomical gap that silver revenue could reverse.

“At the moment, recycling often costs more than landfill. But if recyclers can efficiently recover and sell the silver contained within solar panels, that changes the economics completely,” Firouzi noted. “Silver is the highest-value material in a solar cell. Recovering it has the potential to make solar-panel recycling far more financially attractive.”